Device in a valve

ABSTRACT

A valve ( 1 ) has a valve housing ( 2 ) with an inlet ( 3 ) and outlet ( 4 ), a valve body ( 5 ), provided with an essentially cylindrical passage ( 6 ) and pivotally mounted in the housing ( 2 ). Essentially plane walls, defining chambers between them and provided with through openings ( 11; 11 ′) are arranged in the passage ( 6 ). Upon opening the valve the inlet connects solely with one chamber, which via wall openings and intermediate chambers connects with the chamber opposite and the latter with the outlet. During the successive opening sequence of the valve more and more chambers and finally all chambers are made to connect with the inlet and the outlet respectively. The device has at least one pair of intersecting walls ( 8   a,    8   b;    9   a,    9   b,    10   a,    10   b ). These are located in the passage ( 6 ), so that two opposing chambers (K 1,  K 4;  k 1,  k 9 ) situated nearest to the inlet ( 3 ) and the outlet ( 4 ) respectively lie symmetrically in relation to a center plane, in which the central axis ( 6   a ) of the passage is situated during the rotational movement vice-versa ( 5 ) between the opened and the closed position and vice-versa.

BACKGROUND OF THE INVENTION

It is known that in valves of the said type cavitation and high noiselevels occur in the event of large pressure gradients in liquids.

Devices have been disclosed, for example in the European patentapplications No. 87901700.2 and No. 81302496.5, which are intended toreduce the propensity to cavitation and thereby the noise level. Thesaid devices are relatively complicated to manufacture, however, andtherefore costly.

SUMMARY OF THE INVENTION

The object of the present invention is to produce a device of the saidtype that represents a simplification compared to the prior art.

The device according to the invention affords a number of advantages. Inmanufacturing terms it is very easy to achieve high stability throughthe combination of intersecting walls provided with through openings.This greatly reduces the risk of vibrations occurring as a result ofpressure gradients over the walls. Incoming flows, moreover, are dividedup symmetrically and the divided flows “collide” with one anotherimmediately in front of the outlet. This collision gives rise to afurther pressure gradient, whilst valve damage is minimised even ifcavitation should occur, due to the fact the pressure gradient isabsorbed by the actual collision and consequently to a lesser extent bythe valve material. In the fully opened position an approximatelysymmetrical flow through the valve is achieved with ensuing goodnoise-reducing characteristics and low pressure gradient in thisposition.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail below with reference tothe attached drawing in which

FIG. 1a in a diagrammatic plan view shows a valve and FIG. 1b shows alongitudinal section B—B through the valve in FIG. 1a.

FIG. 2a in a cross-sectional diagram shows the essentially cylindricalpassage through the valve with a pair of intersecting walls according tothe invention. FIG. 2b shows one such wall.

FIG. 3a, like FIG. 2a, shows a passage with two pairs of wallsintersecting one another in pairs, and FIG. 3b shows an example of awall according to FIG. 3a.

FIG. 4a, with a diagram of a valve body in perspective view, illustrateshow the through-flow through the valve body passage occurs with fourwalls arranged therein.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A ball valve 1 comprises a valve housing 2 with inlet 3 and outlet 4arranged on opposite sides thereof. A valve body 5 with an essentiallycylindrical passage 6 is pivotally mounted inside the housing 2. FIG. 1ashows a shaft 5 a connected to the valve body 5 for operation of thevalve body 5. In the fully open position of the valve 1, the inlet 3 andoutlet 4 and the passage are situated in line with one another. FIG. 1balso shows two ring seals 7 a, 7 b that provide sealing between inlet 3and outlet 4 respectively and the valve body 5. The person skilled inthe art will appreciate that in certain applications only one seal isrequired.

According to the invention at last one pair of intersecting walls 8 a, 8b, see FIG. 2a, and 9 a, 9 b and 10 a, 10 b see FIG. 3a, is arranged inthe passage 6. The construction of a pair of walls, which as will beseen from FIGS. 2a and 4 are arranged like a cross in the passage 6,will now first be explained in more detail with reference to the FIGS.2a, 2 b and 4. The space in the passage 6 is divided up by the walls 8a, 8 b into four chambers K1, K2, K3 and K4. The said chambers arelocated so that the chamber K1 lies nearest to the inlet 3 and thechamber K4, which is situated directly opposite the chamber K1, liesnearest to the outlet 4. The walls 8 a, 8 b are identical and forjoining them together are provided with a slit 12, so that they can beinserted into one another. Fitted into the passage 6, the line ofintersection 8 c of the walls 8 a, 8 b coincides with the centre line 6a of the passage. As will be seen from FIG. 2b, the walls 8 a, 8 b areprovided with through-slits 11, inclined in relation to the centre line6 a, preferably in such a way that the projected lines of the slits ontwo successive walls in the direction of flow form a right angle withone another.

As will already have become clear, when the valve body is turned in theopening direction, the following happens:

As the opening movement progresses, an increasingly larger connection isopened between the inlet 3 and the chamber K1 and correspondinglybetween the chamber K4 and the outlet 4. Initially therefore, a mediumflows into the chamber K1, is forced through the slits 11 in the walls 8a, 8 b into the chambers K2 and K3 in two essentially equal flows. Thesaid flows are recombined in the chamber K4 after again passing the slitopenings 11 in the walls that lie between the chamber K4 and thechambers K2 and K3 respectively. The person skilled in the art willappreciate that this results in pressure gradients, viz.:

1. At the passage of the medium from the inlet by way of a small openingand into the chamber K1.

2. At the passage of a half-flow through the slits from the chamber K1to the chamber K2 or at the passage of the other half-flow through theslits from the chamber K1 to the chamber K3.

3. At the passage of the medium half-flows from the chambers K2 and K3to the chamber K4.

4. At the meeting of the medium half-flows in the chamber K4, and

5. At the passage of the medium through a small opening between thechamber K4 and the outlet 4.

As the valve is increasingly opened, the effect of the intersectingwalls 8 a, 8 b will diminish to an extent such that when the valve isfully open the effect is negligible. The valve can therefore absorb verylarge pressure gradients at small opening angles and still have greatcapacity when the valve is fully open. This corresponds, moreover, tothe characteristics of most process systems, in which a pump pressurefalls with increasing capacity, just as the pressure gradient in fixedvalves and pipes increases with an increased flow of medium. The factthat the walls 8 a, 8 b in the fully open valve divide up the flow ofmedium through the valve into four essentially equal flows gives thevalve very good characteristics due to the symmetrical flows.

In the embodiment according to FIG. 3a of the device according to theinvention there are, as stated, two pairs of intersecting walls, that is9 a 9 b and 10 a, 10 b, which as will be seen from FIG. 3b are providedwith circular through-bores 11′ and slits 12 in order to permit assemblyas indicated in FIG. 3a. The pairs of walls 9 a, 9 b and 10 a, 10 b aresymmetrical with their respective lines of intersection 9 c, 10 clocated on either side of the centre line 6 a of the passage 6. Thepassage is divided up by the walls into nine chambers, that is chamberk1, which lies nearest to the inlet 3, chambers k2-k7, chamber k8, whichlies in the centre of the passage 6, and chamber k9, which lies nearestto the outlet 4. For reasons of symmetry the flows of medium in thechambers k2, k3, k6 and k7 are essentially equal and in the main halfthe size of the flows in the chambers k1 and k9.

At a small opening angle the inlet 3 connects solely with the chamber k1and the outlet 4 with the chamber k9. The conditions are similar to whathas already been explained in connection with FIG. 2a and FIG. 4, but itmust be noted that in the embodiment with two pairs of intersectingwalls according to FIG. 3a there are more points of constriction than inthe embodiment with one pair of intersecting walls according to FIGS. 2aand 4.

The constriction may naturally be adjusted by varying the number ofopenings in the walls defining the chambers and/or the size of the saidopenings. It will also be apparent that the valve body need notnecessarily be spherical, and that the invention is also applicable in aspherical sector valve or in a cylindrical/conical throttle valve,provided that the passage is essentially cylindrical.

It will be realised that the device according to the invention is alsoadvantageous in valves for regulating gas or steam flows.

What is claimed is:
 1. Device in a valve (1) comprising a valve housing(2) with inlet (3) and outlet (4) preferably arranged directly oppositeone another on opposite sides of the housing (2) and in the valvehousing (2), between the inlet (3) and the outlet (4), a valve body (5),provided with an essentially cylindrical passage (6) and pivotallymounted in the housing (2) so that with the valve (1) in the fully openposition the passage (6) together with the inlet (3) and outlet (4) liein line with one another, essentially plane walls, defining chambersbetween them and provided with through openings (11; 11′) being arrangedin the passage (6), and the inlet, at the commencement of the valveopening movement, connecting solely with one chamber, which via wallopenings and intermediate chambers connects with the chamber oppositeand the latter with the outlet, with more and more chambers and finallyall chambers being made to connect with the inlet and the outletrespectively during the successive opening sequence of the valve,characterised in that the device comprises at least one pair ofintersecting walls (8 a, 8 b; 9 a, 9 b, 10 a, 10 b), which are locatedin the passage (6), so that two opposing chambers (K1,K4;k1,k9) situatednearest to the inlet and the outlet respectively lie symmetrically inrelation to a centre plane, in which the central axis (6 a) of thepassage is situated during the rotational movement of the valve body (5)between the open and the closed position and vice-versa, so that a flowof medium flowing into the chamber (K1; k1) lying nearest to the inletby way of the openings (11; 11′) in the walls (8 a, 8 b; 9 a, 9 b, 10 a,10 b) is divided up into a plurality of medium flows, which are combinedin the chamber (K4; k9) situated nearest to the outlet, resulting in apressure gradient.
 2. Device according to claim 1, characterised in thatthe device has two pairs of intersecting walls (9 a, 9 b, 10 a, 10 b),which are in parallel pairs and the lines of intersection (9 c, 10 c) ofwhich are situated on either side of and parallel with the centre-line(6 a) of the passage (6).
 3. Device according to claim 1, characterisedin that the openings (11) are slit-shaped.
 4. Device according to claim3, characterised in that the slits are uniformly inclined in relation tothe central axis of the passage, preferably in such a way that in thecase of two adjacent walls they form a right angle with one another. 5.Device according to claim 1, characterised in that the openings (11′)are circular ducts.
 6. Method in a valve (1) with a valve housing (2)with a valve body (5), pivotally mounted therein and with an essentiallycylindrical passage (6), which with the valve (1) in the fully openposition lies in line with inlet (3) and outlet (4) located on oppositesides of the housing, characterised in that at least one pair ofintersecting, essentially plane walls (8 a, 8 b; 9 a, 9 b, 10 a, 10 b)are located in the passage (6) and are provided with through-flowopenings (11; 11′), the walls (8 a, 8 b; 9 a, 9 b, 10 a, 10 b) beingoriented so that two opposing chambers (K1, K4; k1-k9), defined byintersecting plane walls and by the cylindrical wall of the passage, aresituated symmetrically in relation to the inlet (3) and the outlet (4),a flow of medium being introduced into the chamber (K1; k1) situatednearest to the inlet to be divided up via the openings (11; 11′) in thewalls (8 a, 8 b; 9 a, 9 b, 10 a, 10 b) into a plurality of medium flowsso as to produce a pressure gradient, which are then combined in thechamber (K4; k9) situated nearest to the outlet.
 7. Method according toclaim 6, characterised in that two pairs of intersecting walls (9 a, 9b, 10 a, 10 b) are located with walls in parallel pairs and that theseare aligned so that the intersecting walls or lines of intersection (9c, 10 c) are located on either side of and parallel with the centre-line(6 a) of the passage.